Art of road making



Patented June 19, 1928.

UNITED S TA'lES PATENT OFFICE.

SAMUEL SADTLER, OF SPRINGFIELD TOWNSHIP, MONTGOMERY COUNTY, PENN SYL- VANIA, ASSIGNOR TO AMIESITE ASPHALT COMPANY OF AMERICA, 0]? PHILADEL- PHIA, PENNSYLVANIA, A CORPORATION OF NEW JERSEY.

ART or ROAD MAKING.

No Drawing.

This invention relates to improvements in the art of roadmaking', and the principal object of the invention is to provide novel and improved means for coating damp stone, constituting the aggregate of which the road composition is made, with asphalt or other bitumen.

Another object of the invention is to provide a novel and improved method particularly applicable to the coating of limestone and stone of like alkaline nature.

It is frequently desirable to make roadways of the general type set forth in U. S. Patent No. 1,611,444, without special drying of the stone of the aggregate in preparation for coating the stone with bitumen. Difliculty, however, has been experienced in the absence of the drying operation of obtaining a satisfactory bond between the bitumen and the surfaces of the stone. It has been particularly difficult to obtain satisfactory results under the stated circumstances in connection with roadways or surfaces in which the voids between the bitumen-coated stones are not filled and in which the stones are cemented together solely or principally by their asphaltic or bitumen coatings.

- With certain stones of dense character in which ferro magnesium minerals predominate, such for example as gabbro or basalt, light hydrocarbon oils such as kerosene and naphtha and bitumens such as asphalt dc rived from petroleum have a preferential affinity for the stone surfaces even when the,

surfaces are somewhat damp. For minerals of this character, I find it sufiicientto add light hydrocarbon oils of a slowly volatile nature, such as kerosene, to the aggregate;

A and after agitation, in a pug mill for example, it will be found that the kerosene or other liquefier will displace whatever water there may be on the stone surfaces, and satisfactorily prepare the surfaces for reception of the asphalt or other bitumen, which is then added. By this means a satisfactory coating can be obtained with the bitupnen in intimate contact with the stone suraces.

In this process I may use about one gallon or one and one-half gallons of the liquefier, which as stated above may be kerosene or other slowly volatile light hydrocarbon oil,

not respond to the above process.

Application filed March as, 1927. Serial No. 178,814.

to 1900 lbs. of stone. Preferably the stone is heated to'a temperature between and 90 F. To this liquefier-treated stone I then add melted asphalt at a temperature of say 212 F. or slightly higher to the extent of about 80 to 100 lbs., depending upon the size of the stone and using less asphalt for stone of larger sizes such as would be used for a base course, and larger quantities for stone of the smaller sizes such as may be ,used for the top or wearing course of the finished roadb'ed. After the asphalt has been thoroughly incorporated and spread through the stones and over all the surfaces, I preferably add from 6 to 10 lbs. of hydrated lime, which is thoroughly distributed through the mass when the operation of coating is completed.

I have found, however, that certain types of stones, and particularly limestone, do

Limestone when at all damp and often when containing as little as a few tenths of a percent of moisture will not take a commercial coating of bitumen with the aforedescribed rocedure. Under some conditions, the asp alt may be spread over the surfaces of thestone with the use of a liquefier as described, but it will not adhere and will have a tendency to peel off. Where such materials are used in roadways, the stones may actually become loose from one another and result in complete failure of the road surface.

I have discovered that by dissolving in the liquefier some form of soap containing unneutralized acids, the attraction of the bitumen or asphalt to stone of alkaline nature such as limestone is promoted, with the result that a firm bond between the asphalt and stone surfaces is obtained. I prefer to use some form of sulfonated oil partly neutralized with ammonia, although simple organic acids such as oleic, partly neutralized with ammonia, will be found satisfactory. In any case, the acid is only procedure and the proportions of the other ingredients of the mix being substantially the same as those recited above.

I do not, however, limit myself to any particular quantities or proportions.

I claim:

1. The method of coating stone of alkaline nature, which consists, in taking a bitumen liquefier such as kerosene, dissolving therein a soap containing unneutralized acid, treating the stone with the liquefier composition, and thereafter incorporating a bitumen.

2. The method of coating damp stone of alkaline nature,'which consists in taking a bitumen liquefier to which has been added a soap containing unneutralized acid, said soap being soluble in the liquefier, treating the stone with said mixture, and thereafter adding a bitumen. 1

3. The method of coating damp stone of alkaline nature, which consists in taking a bitumen liquefier such as kerosene, adding thereto a sulfonated oil partly neutralized with ammonia and soluble in the liquefier, treating the stone with said mixture, and thereafter incorporating a bitumen.

4. The method of coating damp stone of an alkaline nature, which consists in adding to a bitumen liquefier such as kerosene an 'orgamc acid such as o1e1c partly neutralized with ammonia and soluble in the liquefier, treating the stone with said mixture, and thereafter incorporating a bitumen.

SAMUEL S. SADTLER. 

